Ammonia Emissions in Europe

Ammonia emissions are mainly related to agricultural activities, and depositions related to these emissions constitute a treat to local ecosystems but possibly also to human health through the contribution for formation of secondary fine fraction particles in ambient air. European ammonia emissions are highly heterogeneously distributed, and the temporal variations in these emissions follow\ud very different pattern as a result of differences in climate but also as a results of significant differences in agricultural practice over Europe. A minor fraction of\ud ammonia emission is related to nonagricultural sources, especially traffic. These sources are mainly found in areas with intense traffic and the use of catalyst converters. Simple and comprehensive models for the spatial and temporal variation in ammonia emissions have been shown useful in modelling of atmospheric nitrogen input to sensitive ecosystems for assessments of critical loads. For the spatial distribution various emission inventories are available at different resolutions. These inventories are derived using different approaches, and as a result they can\ud differ up to a factor of two for certain areas. The overall European ammonia emissions are decreasing as a result of regulation related to the National Emission Ceiling Directive (NEC) and the Integrated Pollution Prevention and Control (IPPC) directive, regulation that has been implemented in national legislation in the single European countries. Some countries have adopted screening methods to be used by local authorities when assessing impact on local ecosystems in relation to applications from farmers to obtain permissions to increase agricultural production.\ud In general Northern European countries have more strict regulation of ammonia emissions compared with Central and Southern European countries